Manufacture of seamless tubes.



S. E. DIESGHER.

MANUFACTURE or SEAMLESS TUBES.

APPLICATION TILED $313.3 1911.

Patented Mar.18,1913.

2 SHEETS-SHEET 2.

WITNESSES: I i V V mvENTbR- 9;; 996 j 8.1km Junkufiflhg 'Any- SAMUELDIESCHER, 0F PITTSBURGH, PENNSYLVANIA.

MANUFACTURE OF SEAMLESS TUBES.

Specification of Letters Patent.

Patented Mar. 18, 191 3.

Application filed February 3, 1911. Serial No. 606,440.

To all whom it may concern:

Be it known that I, SAMUEL E. DIESCHER, residing at Pittsburgh, in thecounty of Allegheny and State of Pennsylvania, citizen of the UnitedStates, have invented or discovered certain new and useful Improvementsin the Manufacture of Seamless Tubes, of which improvement the followingis a specification.

As is well known to those skilled in the art it has been. heretoforepractically impossible when piercing is eifected by the conjoint actionof rolls and a mandrel to'produce seamless tubes of uniform ga ethickness of wall. This is due to the act that in piercing the billet anirregular inner surface is produced. This irregularity consistsgenerally of inwardly projecting spiral ribs of a pitch corresponding tothat of the twist of the billet during the piercing operation. Whilethis irregularity is somewhat reduced or modified in the reduction ofthe pierced billet to the finished tube, it has not been possible towholly remove it by any of the methods now in use for reducing thepierced blank.

The invention described herein has for its object the reduction of theirregularities produced in piercing and the production of a blank havinguniform gage or thickness of wall throughout its entire length.

The inventlon is hereinafter more fully described anu claimed.

In the accompanying drawing forming a part of this specification Figurel is a side elevation partly in section of a form of apparatus for thepractice of my invention;

- Fig. 2 is an enlarged sectional View illustrating the press ngsurfaces and mandrel the former being in open :position; Fig. 3 is atransverse section on a plane indicated by the line 111-111 F ig. 2;Fig. 4 is a view similar to Fig. 2 showing the pressing surfaces inclosed position and Fig. 5 is a secplane indicated by the line V-V Fig.4:.

In the practice of my invention theblank 1 as it comes from the piercingmill if it is sufiiciently lastic, or from a heating furnace 2 is slidover a mandrel 3 which is held in position by a bar 4 between pressingsurfaces having one or both a relative to'and fro movement. It ispreferred that these surfaces should be formed by. grooves in the head 5and anvil block 6 of a pfess of any suitable construction. These groovesshouldbe made of such transverse dimensions that when the head and anvilare placed together they form an approximately circular pass a littlesmaller than the external diameter of the pierced billet or blank.Preferably the entrance end of the grooves or pass is made a littlelarger than the opposite or finishing end. In other words the pass ismade slightly tapering. The mandrel 3 is made of a diameter sufiicientlysmaller than the smallest internal diameter of the blank so that thepierced billet made may be easily slid over the mandrel without anywiping or dislodgment of the apices of the inwardly projecting ridges. IAs before stated these ridges or relatively thick bands of metal arespirally disposed along the tube, the

pitch of such spiral corresponding to the twist given to the billet inthe piercing operation. The mandrel should be made of such a lengthrelative to the pitch of the ridges or thick bands-that when the billetis subjected to action of the pressure surfaces the ridge or band willbear at such points on the mandrel to prevent it from be ing shifted toan angle to the axis of the billet. This will be readily understood byreference to Fig. 2. If the mandrel were so short as to be supported bythe ridge only at points a and b, the point of the mandrel would beforced down and there would be only a slight if any reduction of theridge. If however the mandrel were made of a length a little greaterthan the pitch of the ridge the points of support a, b, and 0 of themandrel would be so disposed as to maintain the mandrel centrally. It ispreferred in order to insure the best results that the mandrel shouldhave a length greater than one and a half times the pitch of the ridgeso that there will be an equal number of supports on all sides of themandrel and the reduction of ridge will be uniform. While being fedbetween the pressing surfaces and over the mandrel the billet should ber0- tated so as to be subjected uniformly to reducing pressure. Anysuitable means may .ls befor stated the head and anvil are provided withgrooves which will form when the .head is forced against the anvil as isthe designed operation of the parts, a circular pass, and consequentlyin addition to bringing the walls of the article to uniform gage, thearticle will in the practice of my invention be brought to a uniformexternal diameter throughout its entire length.

l claim herein as my invention:

l. The improvement in the art of manufacturing seamless tubes, themethod herein described which consists in piercing a billot by forcingit over a mandrel by rotating the billet on its axis, andcircumferentially pressing the article so pierced against a centrallymaintained mandrel.

2. The improvement in the art of manufacturing seamless tubes, themethod herein described which consists in piercing a billet by forcingit over a mandrel by rotation on its axis and subjecting the wall of thearticle so pierced to pressure between surfaces of a length greater thanthe distance between ridges due to the piercing operation.

3. The improvement in the art of manufacturing seamless tubes, themethod herein masses described which consists in supporting a mandrel ona plurality of inwardly projecting portions of the tube so distributedalong the inner Wall of the tube as to main tain the mandrel centrally,and subjecting the external surface of the article to pressure extendinga distance along the article greater than the distance between adjacentmandrel supporting portions.

tulhe improvement in the art of manufacturing seamless tubes, the methodherein described which consists in supporting a mandrel on a pluralityof inwardly projecting portions of the tube so distributed along theinner wall of the tube as to maintain the mandrel centrally, andsubjecting the external surface of the article to oppositely actingpressing faces one having a predetermined. movement relative to theother, whereby the walls of the tube are brought to uniform gage and thetube to uniform external diameter.

In testnnony whereof, l have hereunto set my hand.

SAMUEL E. DIESCHER. Witnesses: v

ALICE A. TRILL, THOMAS Joron.

